With fewer herbicide options across the rotation and continuing concern over the increasing incidence of weed resistance, growers are looking beyond to alternative herbicides such as Kerb to control annual meadow-grass and volunteer cereals, as well as brome species and wild-oats in oilseed rape and winter beans. They are able to use lower more cost-effective dose rates to get high levels of control of bigger weeds.
"Many growers are using oilseed rape as an important break crop, particularly for black-grass management, but winter oilseed rape also offers the opportunity to clean up grass-weeds such as annual meadow-grass, as herbicide options diminish in cereals. IPU was the mainstay herbicide for meadow-grass control in cereals and trifluralin was important for a range of grass-weeds in cereals, rape and beans. Current contact graminicides in broad-leaved crops need to be applied to small meadow-grass for best results, limiting flexibility. Their multiple applications each year could inadvertently exacerbate resistance issues in other weeds. This means looking beyond past standard treatments to alternatives such as Kerb in rape and beans," says Rene Pollack of Dow AgroSciences.
"Kerb has always been regarded as a highly active black-grass herbicide, but it is also shows excellent efficacy on annual meadow-grass. Trials show that when used at 1.25 l/ha and applied in October, Kerb gave 100% control of meadow-grass and 99% control when treated in December. Kerb will control meadow-grass up to early tillering stage, so you have flexibility in when you apply it," reports Rene.
"Kerb will also control volunteer wheat or barley, with levels of control in the high nineties. With early drilling promoting an early flush of volunteers, many growers will have already used a contact-acting fop or dim graminicide earlier in the season. We would expect a second flush of volunteers alongside later germinating grass-weeds. Kerb would be an excellent choice at this later timing."
"As Kerb is taken up by the roots of its target weeds, it needs moist soil, cool soil temperatures and a fine even soil surface. These conditions apply to meadow-grass control just as much as they do to black-grass. However meadow-grass is an easier weed to control with Kerb Flo and, even at lower dose rates, exceptional results will be delivered."
Rene Pollak points out where growers may have held off applying their pre-emergence herbicide in oilseed rape this year, because of the very dry early autumn, Kerb will also provide control of a range of common broad-leaved weeds. "The most susceptible is chickweed, which can be killed even when emerged. In addition the product provides pre-emergence activity against black bindweed, black nightshade, fat-hen, knotgrass, redshank, small nettle and speedwells. Superficial seed of forget-me-knot and cleavers are moderately susceptible."
